1. Field of the Invention
This invention relates to a disassembling tool for disassembling a process cartridge detachably attached to an image forming apparatus such as a copying machine, a laser beam printer or a facsimile apparatus.
2. Related Background Art
In an image forming apparatus using an electrophotographic image forming process, there is adopted a process cartridge comprising an electrophotographic photosensitive member and process means for acting on the electrophotographic photosensitive member integrally made into a cartridge which is made detachably attachable to an image forming apparatus main body. According to this process cartridge system, the maintenance of the image forming apparatus can be done by a user himself without resort to a serviceman and therefore, the usability of the image forming apparatus is markedly improved.
As the construction of such a process cartridge, there is one in which two frame bodies are coupled together. For example, a photosensitive member frame body for supporting a photosensitive drum, a charging device and a cleaning device, and a developing device frame body comprising a developing frame body for supporting developing means and a toner frame body having a toner chamber, the developing frame body and the toner frame body being joined together, are coupled together for rotation about a fulcrum. The two frame bodies are biased about the aforementioned fulcrum by a resilient member such as a spring to thereby determine the relative position of the photosensitive drum and the developing means. The functional merits of adopting the above-described construction are that the pressure force of a developing roller against the photosensitive drum can be made proper, and that the interval between the surface of the photosensitive drum and the surface of the developing roller can be maintained constant. Further, the use of the aforedescribed two frame bodies leads to many merits such as the facilitation of the molding of the frame bodies and the facilitation of assembly.
In the above-described conventional process cartridge, an engagement pin bringing a developing device unit and a photosensitive member unit into engagement with each other is required to have sufficient withstanding pull-out strength to ensure the engagement between the two units. Also, the engagement pin is installed so as to be fully embedded in a holding portion so that the user may not pull out the engagement pin by mistake.
To disassemble the process cartridge, the engagement pin coupling the two units together is pulled out, and the process cartridge is disassembled into the developing device unit and the photosensitive member unit.